const fs = require('fs')
fs.readFile(__dirname + '/test.txt', 'utf8', function (err, dataStr) {
  if (err) {
    console.log('读取失败' + err.message)
  } else {
    console.log(dataStr);
  }
})
fs.writeFile(__dirname + '/test.txt', '你不好' + Date.now(), 'utf8', function (err) {
  if (err) {
    console.log(err.message)
  } else {
    console.log('写入成功');
  }
})
